- Michael (1992, paternal half brother, about 10 months older)
- Pauline (full sister, 1994)
- Camille (maternal half sister, 1998)
- Unnamed Paternal half sister (guessing here, 2011?)
His maternal aunt and uncle, Princess Caroline and Prince Albert are his godparents (Source:The Royal House of Monaco: Dynasty of Glamour, Tragedy & Scandal, p 254).
He attended local Monaco public schools, until he was uprooted when he, his mother and sisters joined the circus. He has also studied in Switzerland (briefly), France and the USA. He is fluent in several languages, including French, lang Monégasque and Italian. During the early 2000s, along with his mother and two sisters, he traveled with the Kline Circus for a few years. He graduated from Lyccee Prince Albert 1er in 2011, and went on to attend SKEMA Business School, studying sports management.
He rarely appears in public on behalf of the Monégasque Princely Family. However, in 2014, he made very few brief appearances including the Star Team for children and World Stars football match during the Monaco Grand Prix Week and opening of the Monaco Yacht Club inJune with his entire family (I mean entire...99% of them were there!). In 2005, along with his little sister, he appeared on the reality television show, La Ferme Célébrités. In 2013, during the Grand Prix Week, he played in a charity football match, and at the end of the summer, he alongside his mother and younger sister appeared at the FIGHT AIDS Monaco Gala. In 2015, he attended the unveiling of his new cousins to the public in January, their christening in May, his uncle's 10 year enthronement celebrations & his cousin Pierre's civil wedding ceremony in July, as well as the 2015 Fight Aids Monaco Gala in July, his cousin Pierre's religious ceremony in August, the 2015 Golden Foot Awards in September and Monaco's National Day celebrations in November. In 2016, he was present at several days of the 40th International Circus Festival and **New Generation** Festival, he joined his aunt and uncle for the Monaco Grand Prix, was joined by his uncle and girlfriend for the closing ceremony of the 2016 56th Monte Carlo TV Festival, attended UEFA Euro 2016 final match between Portugal and France, attended day 2 of SPORTEL Monaco 2016 and the Golden Foot Awards, and most recently, he was present during the national day festivities
Louis, along with little sister Pauline (and most of the rest of the Grimaldis), is a major fan of Monaco’s home football team, AS Monaco FC. When Louis was a youngster, Prince Albert joked that they may have to change the name of the Monégasque stadium to Stade Louis III from Stade Louis II, in his honor.
He was originally to be named something else, but at last minute, he was named Louis for his maternal great-grandfather, Louis II. Presently, he is 9th in line for the Monegasque throne after his aunt Caroline, six cousins (Andrea, Pierre, Charlotte, Alexandra, Gabriella & Jacques), and his mother Stephanie, however with the pending 2017 birth of Princess Caroline's second grandchild from her son Pierre and daughter-in-law Beatrice, he will move down in succession to occupy 10th Place. Louis does not bear the title HSH Prince of Monaco at his parents' request to give him a semi-normal life, given how far down the line of succession he is in line.